Personnel location system



April 15;1969

J. E. WARD PERSONNEL LOCATION SYSTEM Filed Sept. 21, 1967 l VVENTOR.

3,439,320 PERSONNEL LOCATION SYSTEM llames E. Ward, Glendora, Calif.,assignor to Relton Corporation, Arcadia, Calif., a corporation ofCalifornia Filed Sept. 21, 1967, Ser. No. 669,610 lnt. Cl. G01s 3/80 US.Cl. 340-16 7 Claims ABSTRACT OF THE DISCLOSURE of the location of thisperson at a designated area. Preferably, the indication is maintaineduntil the person moves to a different area and actuates his transmitterthere.

Background of the invention This invention relates to communicationbetween a plurality of persons and a central point and, moreparticularly, to an indication system for locating personnel at a largefacility.

At large business establishments, hospitals, construction sites, andother extended areas of activity, provision must be made forcommunicating with personnel that move about the area in the course oftheir work. Most known systems for accomplishing this type ofcommunication have disadvantages of one sort or another that must betaken into consideration and weighed when selection of a particularsystem is made. For the most part, the person sought is paged in one wayor another.

Probably the most commonly employed paging system is a public addressnetwork in which the name of the person sought is .announced overloudspeakers distributed throughout the entire facility. Communicationin this type of system is not selective, i.e., the pages are heard byeveryone within the facility regardless of whether or not a person isaffected by the announcement being made. Continual paging over such apublic address network often disturbs the personnel and thereforereduces the efficiency of their activities.

Other paging systems are selective and therefore do not disturbpersonnel who are not concerned with the page. These systems employ oneor more radio frequency transmitters distributed throughout thefacility. The transmitters are capable of producing one of a pluralityof different frequencies. Each person to be paged has in his possessiona radio receiver tuned to a unique one of these frequencies. Tocommunicate with a person, his unique frequency is broadcast by all thetransmitters, thereby producing only in his receiver an audibleindication that can be heard by him. This type of system requires aportable source of electrical energy in each receiver on which a currentdrain is continually imposed as long as the receiver is in a stand-bycondition. When the energy source is expended, it must be replaced orrecharged in order to maintain its operation.

on the concept that personnel are located in response to signals sentout by them each time they move to a different nited States Patent Odesignated area at a facility. Specifically, each person has in hispossession a transmitter capable of producing a locating signal having aunique frequency. Each area or room at the facility to be designated isprovided with a transducer or receiver capable of sensing all the uniquefrequencies assigned to the personnel. The transducers are all coupledto a centrally located display panel capable of indicating thedesignated area in which each person is located. When a person actuateshis transmitter, thereby sending a locating signal to the transducer inthe area or room in which he is located, control circuitry determineswhich unique frequency is being received at the central location andwhich transducer is sensing this unique frequency. An indication of thelocation of the person sending the signal at one of the designated areasis then produced on the display panel responsive to the controlcircuitry. Most advantageously, this indication is maintained on thedisplay panel until the person sends out a signal from his transmitterin a diiferent designated area, at which time a new indication replacesthe original one.

Preferably, the locating signals are produced by ultrasonic soundtransmitters. In such case, the system produces no audible sounds thatmay disturb other personnel, and no portable sources of electricalenergy are required for the units in the possession of the person to belocated. The energy for actuating the ultrasonic transmitter could beprovided by the person operating the transmitter in the form of a hammerblow on an ultrasonic resonant tuning fork or the like.

Brief description of the drawing The features of a specic embodiment ofthe invention are illustrated in the drawing, in which:

FIG. 1 is a schematic diagram in block form of a communication systemincorporating the principles of the invention; and

FIG. 2 is a circuit schematic diagram of a portion of the display panelcontrol circuitry of FIG. 1.

Description of a specific embodiment In connection with FIG. l, apersonnel location system is described that indicates the location of vepersons designated JIM, MAX, BUD, JOE, and BILL at one of three areas ofa facility designated ROOM 1, ROOM 2, and ROOM 3. Each person isprovided with a transmitter capable of producing an ultrasonic soundsignal having a unique frequency. The ultrasonic frequencies aredesignated f1, f2, f3, f4, and f5. Preferably, the ultrasonictransmitters are of the type that produce ultrasonic signals in responseto a hammer blow so that no portable source of electrical energy isrequired in the transmitters. Such ultrasonic transmitters are in commonuse to control remotely commercial television receiver sets in the home.Instead, a portable power source could be used to give a constant signalor a selectively intermittent signal. The areas encompassed by ROOM 1,ROOM 2, and ROOM 3 are represented schematically in FIG. 1 by blocks 10,11, and 12, respectively. Ultrasonic transducers or receivers 13, 14,and 15, which each have a band width sufficiently wide to sense all ofthe frequencies f1 through f5, are provided in ROOM 1, ROOM 2, and ROOM3, respectively. Transducers 13, 14, and 15, which convert ultrasonicsound energy to electrical energy, are coupled through ampliers 16, 17,and 18, respectively, to centrally located display panel controlcircuitry 19. A display panel 20 in the form of a grid with rows andcolumns of indicators, such as lamps, is also provided at the centrallylocated point. Each indicator on display panel 20 is situated in asquare area of the grid. One horizontal row of indicators is providedfor each room to be designated,

and one vertical column of indicators is provided for each person to beidentified.

When a person enters a room, he actuates his transmitter, therebysending an ultrasonic signal to display panel control circuitry 19. Thisis illustrated in FIG. 1 by an ultrasonic transmitter 21 in ROOM 1 thatproduces an ultrasonic sound signal at frequency f1 assigned to JIM. Theultrasonic sound signal is represented at 22. Display panel controlcircuitry 19 senses which one or more of the frequencies f1 through f5is being sent and which transducer is receiving this frequency. On thebasis of this information, the location of the person involved at adesignated area is determined and indicated on display panel 20responsive to control circuitry 19. Following the assumption thattransmitter 21 is actuated in ROOM 1, a lamp is lit in the upperleft-hand square on display panel 20, designated 23. The lamp remainslit in square 23 until transmitter 21 is actuated in a different room,at which time a new indication replaces the indication in square 23. Thecentral operator can then inform interested people as to JIMs precisewhereabouts or can communicate directly with him without disturbinganyone other than the occupants of his room.

In FIG. 2, a schematic circuit diagram of that portion of display panelcontrol circuitry 19 associated with ROOM 1 is shown. The same circuitrywould be repeated for ROOM 2 and ROOM 3. Lamps corresponding to each ofthe ve squares in the row for ROOM 1 are energized under the control ofrelays. The control coil of each relay is designated by a capitalletter, and its contacts are designated by small letters correspondingto the capital letters with different subscripts Where plural contactsare involved. In accordance with well-accepted practice, normally opencontacts are designated by a cross and normally closed contacts aredesignated by a slash. Relay coils A, B, and C are labeled SR and SO todesignate that they are slow operating and slow releasing relays. Theremaining relays are assumed to operate and release instantaneously.Three out of the five indicator lamps for ROOM 1, designated 30, 31, and32, and the associated control circuitry are shown in FIG. 2. Identicalcircuitry would be employed for the other lamps associated with ROOM 1.The output of amplifier 16 (FIG. 1) is connected through a filter 33 torelay coil A, through filter 34 to relay coil B, and through filter 35to relay coil C. Filters 33, 34, and 35 are selective filters havingnarrow bands that will pass only the frequency assigned to the personidentified by the corresponding column of display panel 20, namelyfrequencies f1, f2, and f5, respectively. On the application of a signalat frequency f1, relay coil D operates immediately to complete a circuitthrough contact d to relay coil X. As described in detail below, theoperation of relay coil X serves to deenergize any other lamps in thecolumn of display panel 20 identifying JIMs location. After a shortdelay, relay coil A operates. Consequently, contact a3 opens tointerrupt the energizing circuit for relay coil D, so that relay coil Xreleases. Contact a1 closes to complete a circuit from a source 36 ofpositive potential to lamp 30. Contact a2 closes to complete a latchingcircuit from source 36 to relay coil A. As a result, relay coil Aremains latched after the signal received from ROOM 1 terminates. Relaycoil A remains latched and indicator lamp 30 remains lit untiltransmitter 21 (FIG. 1) sends an ultrasonic signal to the transducer ina different room.

The outputs of the filters corresponding to filter 33 that select thefrequency f1 from the transducers leading from the other rooms are alsoconnected to relay coil X through a normally open contact controlled bya coil corresponding to coil D. As in the case of lamp 30 and relay coilA, relay coil X has a normally closed contact in the latching circuitfor the lamp energizing the relay coils for ROOMS 2 and 3. Whenever asignal at frequency f1 is received from the transducers in any of therooms, relay coil X is energized for a short period of time as describedabove, thereby opening the latching circuit for the lamps in thecorresponding column. Accordingly, any previously energized lamp in thecolumn is extinguished and the lamp in the row corresponding to thetransducer from which the signal is being received becomes lit.

The control circuitry associated with the lamps in the other columnsoperates in the same manner. Relay coils B and C correspond to relaycoil A; relay coils E and G correspond to relay coil D; and relay coilsY and Z correspond to relay coil X.

What is claimed is:

1. A communication system comprising;

a plurality of portable transmitters each generating a unique signal;

a plurality of fixed receivers positioned to cover different areas at afacility, each receiver being capable of sensing any of the uniquesignals generated by the transmitters;

a display capable of individually indicating the receivers and thetransmitters; and

means connected between the plurality of receivers and the display forindicating on the display which receivers are sensing signals and whichtransmitters are producing the signals sensed by the respectivereceivers.

2. The communication system of claim 1, in which the transmitters eachgenerate an ultrasonic sound signal and the receivers are ultrasonictransducers capable of converting ultrasonic sound energy intoelectrical energy.

3. The communication system of claim 1, in which the transmitters eachgenerate a signal having a unique frequency and the receivers arecapable of sensing signals having the frequencies of all thetransmitters.

4. The communication system of claim 1, in which the indicating meansretains an indication that a receiver is sensing the unique signalproduced by a transmitter until another receiver senses the uniquesignal produced by the same transmitter, causing the indicating means toindicate that the other receiver is sensing the unique signal.

5. The communication system of claim 1, in which the display has aplurality of indicators equal in number to the product of the number oftransmitters and the number of receivers and the indicating meanscomprises control circuitry that energizes the indicator correspondingto the receiver sensing a signal and the transmitter sending the sensedsignal.

6. The communication system of claim 1, in which the display forms agrid having a number of areas equal to the product of the number oftransmitters and the number of receivers, an indicator being located ineach area, and the indicating means energizes the indicatorcorresponding to the receiver sensing the signal and the transmittersending the sensed signal.

'7. The communication system of claim 1, in which the display forms agrid of areas arranged in rows and columns, the grid has a columncorresponding to each transmitter and a row corresponding to eachreceiver, an indicator is located in each area, and the indicating meansenergizes the indicator in the area Where the row that corresponds tothe receiver sensing a signal and the column that corresponds to thetransmitter generating the sensed signal intersect.

References Cited 3,238,503 3/1966 Uitermark et al. 340-311 X RICHARD A.FARLEY, Primary Examiner.

U.S. C1. X.R.

